Valves for switching between a plurality of vacuum or pressure lines are finding increasing use in today's automobile and truck engines due in part to the need for controlling a proliferating array of accessory equipment relating to fuel economy and emission control, for example, exhaust gas recirculators and evaporator canisters. Prior art devices have often been characterized by the use of slider or lip seals passing over the edge of an orifice. Valve life for this type of device has been shortened by excessive wear of the seal members. Other multiport prior art valves have utilized separate fluid chambers in cooperation with complicated and expensive flexible diaphragms. A further problem associated with prior art devices is that of available space around the engine block. This is particularly a problem with valves which are actuated by a thermal sensor, where it has been necessary to provide each valve with a separate threaded access hole in the engine block for connections thereto as, for example, to the engine cooling system. A further disadvantage associated with prior art devices is that heretofore each valve required its own thermally responsive actuator, thus requiring a plurality of element in the valve which has inherently the greatest manufacturing cost.